if __name__=='__main__':
	from Tkinter import *
	x=360
	y=160
	top=y-30
	bottom=y-30
	canvas=Canvas(width=400,height=600,bg='white')
	for i in range(20):
		canvas.create_oval(250-top,250-bottom,250+top,250+bottom)
		top-=5
		bottom+=5
	canvas.pack()
	mainloop()
	